Method of estimating well productivity along a section of a wellbore

Abstract

Disclosed is a system and a method of estimating a well inflow profile along a section of a wellbore of a well passing through a formation. The method comprises: collecting field data as a function of time during testing of the well, analyzing the collected field data to obtain selected field parameters, providing a created dynamic simulation model of the well inflow profile of the well based on at least the geometry of the well, defining a number of different possible inflow profile scenarios, simulating the defined inflow profile scenarios by means of the dynamic simulation model, analyzing the simulated inflow profile scenarios to obtain characteristics of intermittent or slug flow behavior in the form of selected modelling parameters as a function of time, comparing the selected modelling parameters as a function of time for each inflow profile scenario to the corresponding selected field parameters as a function of time and identifying the most likely inflow profile scenario on the basis thereof, and estimating the well inflow profile along the section of the wellbore based on the comparison of the selected modelling parameters as a function of time to the corresponding selected field parameters as a function of time.

The invention claimed is: 
     
       1. A method for efficiently operating a well, comprising:
 estimating a well inflow profile along a section of a wellbore of a well passing through a formation, by:
 collecting field data from a downhole gauge arranged between a reservoir section and a tubing head as a function of time during testing of the well, 
 analyzing the collected field data, which field data is only recorded downstream of the producing interval and measured at the position of the downhole gauge to obtain selected field parameters, 
 providing a created dynamic simulation model of the well inflow profile of the well based on at least the geometry of the well, 
 defining a number of different possible inflow profile scenarios, 
 simulating the defined inflow profile scenarios by means of the dynamic simulation model, 
 analyzing the simulated inflow profile scenarios to obtain characteristics of intermittent or slug flow behavior in the form of selected modelling parameters as a function of time, 
 comparing the selected modelling parameters as a function of time for each inflow profile scenario to the corresponding selected field parameters as a function of time and identifying the most likely inflow profile scenario on the basis thereof, 
 estimating the well inflow profile along the section of the wellbore based on the comparison of the selected modelling parameters as a function of time to the corresponding selected field parameters as a function of time to thereby select a manner in which to operate the well, and 
 operating the well according to the selected manner, 
 
 wherein estimating the well inflow profile according to the steps above obviates the need to run measurement tools into the well, which have high cost and which pose high operational risk. 
 
     
     
       2. The method according to  claim 1 , wherein the method comprises:
 creating the dynamic simulation model taking into account modelling input at least in the form of the geometry of the well, such as diameters and/or deviation survey for the wellbore, 
 defining the number of different possible inflow profile scenarios, 
 simulating the defined inflow profile scenarios by means of the dynamic simulation model, 
 analyzing the simulated inflow profile scenarios to obtain the characteristics of intermittent or slug flow behavior in the form of the selected modelling parameters as a function of time, 
 comparing the selected modelling parameters as a function of time for each inflow profile scenario to the corresponding selected field parameters as a function of time and identifying the most likely inflow profile scenario on the basis thereof, 
 by iteratively adjusting the defined inflow profile scenarios, 
 using the best obtained match between the result of said analysis and the collected field data as the estimated well inflow profile along the section of the wellbore. 
 
     
     
       3. The method according to  claim 1 , whereby the selected modelling parameters include at least one of the parameters pressure, temperature and flow behavior. 
     
     
       4. The method according to  claim 1 , whereby the selected modelling parameters include any combination of:
 Bottom hole pressure, 
 Bottom hole temperature, 
 Tubing head pressure, 
 Tubing head temperature, 
 Flow line pressure, 
 Flow line temperature, 
 Separator temperature, 
 Separator gas rate, 
 Separator oil rate, 
 Separator water rate, 
 Lift gas injection rate. 
 
     
     
       5. The method according to  claim 1 , whereby the characteristics of intermittent or slug flow behavior are described by at least one of the parameters volume, velocity and frequency of the slugs. 
     
     
       6. The method according to  claim 1 , whereby the dynamic simulation model is created taking into account furthermore at least one of the following modelling inputs:
 Fluid phase property models, 
 Flow line geometry, 
 Separator setting and operational input, 
 Separator pressure, 
 Possibly further reservoir properties. 
 
     
     
       7. The method according to  claim 1 , whereby the collection of selected field data as a function of time during testing of the well is performed at least during steady state tests. 
     
     
       8. The method according to  claim 1 , whereby the collection of selected field data as a function of time during testing of the well is performed at least during step rate tests, whereby the flow rate is respectively increased and/or decreased. 
     
     
       9. The method according to  claim 1 , whereby the collection of selected field data is performed downstream of the producing interval. 
     
     
       10. The method according to  claim 1 , whereby the collection of selected field data is performed at the tubing head. 
     
     
       11. The method according to  claim 1 , whereby the collected field data are analyzed to recognize dominant frequencies in the frequency domain achieved from Fourier transform, wavelet analysis, or similar signal processing methods. 
     
     
       12. The method according to  claim 1 , whereby the shape of the temperature signals is analyzed, preferably in the deviation range of less than 0.028 degrees Celsius (0.05 degrees Fahrenheit), more preferred less than 0.0056 degrees Celsius (0.01 degrees Fahrenheit), even more preferred less than 0.0028 degrees Celsius (0.005 degrees Fahrenheit) and most preferred less than 0.00056 degrees Celsius (0.001 degrees Fahrenheit). 
     
     
       13. The method according to  claim 1 , whereby the shape of the pressure signals is analyzed, preferably in the deviation range of less than approximately 70,000 Pa (10 psi), more preferred less than 35,000 Pa (5 psi), even more preferred less than 7,000 Pa (1 psi), even more preferred less than 700 Pa (0.1 psi) and most preferred less than 70 Pa (0.01 psi). 
     
     
       14. A system for efficiently operating a well, the system includes:
 computer program storage; and 
 a processor in communication with the computer program storage, wherein the computer program storage stores a computer program executable by the processor for causing the processor to perform acts comprising: 
 estimating a well inflow profile along a section of a wellbore of a well passing through a formation by:
 collecting field data from a downhole gauge arranged between a reservoir section and a tubing head as a function of time during testing of the well, 
 analyzing the collected field data, which field data is only recorded downstream of the producing interval and measured at the position of the downhole gauge to obtain selected field parameters, 
 providing a created dynamic simulation model of the well inflow profile of the well based on at least the geometry of the well, 
 defining a number of different possible inflow profile scenarios, 
 simulating the defined inflow profile scenarios by means of the dynamic simulation model, 
 analyzing the simulated inflow profile scenarios to obtain characteristics of intermittent or slug flow behavior in the form of selected modelling parameters as a function of time, 
 comparing the selected modelling parameters as a function of time for each inflow profile scenario to the corresponding selected field parameters as a function of time and identifying the most likely inflow profile scenario on the basis thereof, 
 estimating the well inflow profile along the section of the wellbore based on the comparison of the selected modelling parameters as a function of time to the corresponding selected field parameters as a function of time to thereby select a manner in which to operate the well, wherein the well is subsequently operating according to the selected manner 
 
 wherein estimating the well inflow profile according to the acts above obviates the need to run measurement tools into the well, which have high cost and which pose high operational risk. 
 
     
     
       15. A computer program comprising program code means for performing the steps of  claim 1 . 
     
     
       16. The method according to  claim 1 , wherein the inflow profile is estimated based entirely on measurements made outside of the producing interval.